1. BCC prediction of East-Asian key circulation patterns in 2017 summer
FOCRAII
BCC prediction of East-Asian key circulation patterns in 2017 summer
Good morning ladies and gentleman, here comes my topic, BCC prediction of East-Asian key circulation patterns in 2017 summer, my name is zhoufang, from Beijing climate center in China.
Fang Zhou
Laboratory for Climate Studies
Beijing Climate Center
2017/04/25

2. contents 1、Introduction
2、Prediction of East-Asian key circulation patterns
2.1、Prediction of WPSH
2.2、Prediction of SAH
2.3、Prediction of EASM
2.4、Prediction of PSAC
My report contains three parts. Introduction, Prediction of East-Asian key circulation patterns, and Conclusion. The second part mainly contains the precipitation of WPSH, SAH, EASM, and PSAC.
3、 Conclusion

3. contents
1、Introduction

4. 1 Introduction
China is located in the East Asian monsoon region, climate disasters caused by circulation anomalies in East Asia have a significant impact on China, especially in the eastern region. Therefore, the prediction of East-Asian key circulation patterns is of great significance for disaster prevention；
Western Pacific Subtropical High (WPSH), South Asia High (SAH), East Asian Summer Monsoon (EASM), and Philippine Sea anomalous Anti Cyclone (PSAC) are key patterns of East-Asian circulation system, the intensity and position changes have an important influence on climate change；
The latest climate models have been put into operation and provide monthly forecast data in real time. We can use climate models to predict the key circulation patterns in East Asia.

5. contents 2、Prediction of East-Asian key circulation patterns
2.1、Prediction of WPSH
2.2、Prediction of SAH
2.3、Prediction of EASM
2.4、Prediction of PSAC

6. Intensity, Area, and Ridge Point Center Intensity, and Longitude
2 Prediction of East-Asian key circulation patterns
Prediction
BCC_CSM1.1(m)
2017 April
JJA
CFSv2
2017 April
JJA
Models
ECMWF
2017 April
JJA
Initial Month
WPSH
SAH
EASM
Liu Yunyun (2012)
Zhang Q and YF Qian (2000)
Zhang QY (2003)
Intensity, Area, and Ridge Point
Center Intensity, and Longitude
U850
PSAC
B Wang (2000)
SLP
Forecast Month
Indices
In this work, we use three models to do the prediction, BCC model, CFS, and EC model. The initial month is April 2017, and to predict 2017 JJA. The WPSH index here used is defined by Liu yunyun and can characterize the Intensity, Area, and Ridge Point of WPSH. The SAH index is designed by Zhang Qiong and YongFu Qian that can characterize the Center Intensity, and Longitude of SAH. The EASM and PSAC indices used here are Zhang QY and BinWang’s definitions respectively. The details of each index can be found in the CMDP website.
Definitions
Prediction

7. Prediction of Western Pacific Subtropical High (WPSH) Intensity, Area, and Ridge Point indices
Firstly let’s see the Prediction of Western Pacific Subtropical High (WPSH) Intensity, Area, and Ridge Point indices. Both in the BCC, CFS, and EC models, the intensity of WPSH tends to be stronger than normal in 2017 summer. So does the ensemble result of the three model. The forecast skill can almost reach 0.9

8. Prediction of Western Pacific Subtropical High (WPSH) Intensity, Area, and Ridge Point indices
The Area index also tends to be stronger in 2017 summer in the three models. The forecast skill of ensemble result also can reach 0.9

9. Prediction of Western Pacific Subtropical High (WPSH) Intensity, Area, and Ridge Point indices
The ridge point tends to be westward, but the skill will be lower than the intensity and area

10. Prediction of South Asia High (SAH) Center Intensity, and Longitude indices
Secondly, the SAH intensity also tends to be stronger, which can be seen in all the three models. The skill of ensemble result will be higher than any single model

11. Prediction of South Asia High (SAH) Center Intensity, and Longitude indices
The center point tends to be eastward

12. Prediction of East Asian Summer Monsoon (EASM) indices
Since the WPSH and SAH are all stronger in 2017 summer, the EASM index also shows a stronger summer monsoon in this summer, but not that much. The ensemble forecast skill of the three model can reach almost 0.7

13. Prediction of Philippine Sea anomalous Anti Cyclone (PSAC) indices
At last, the PASC in the lower level tends to be weaker

14. contents
3、 Conclusion

15. 3 Conclusion
Based on the latest model predictions of BCC_CSM1.1(M), CFSv2 and ECMWF, the results show that the intensity and area of WPSH in 2017 summer will be slightly stronger and larger than normal, the ridge point tends to be westward.
The intensity of SAH will be stronger than normal and the center location tends to be eastward.
Such a circulation configuration advantages to a strong EASM, which can be clearly seen by the model prediction of EASM index.
Model prediction also shows that the PSA may be weak in 2017 summer.
Here comes my conclusion.

16. 3 Conclusion
Since Zhang-EASM index has a high correlation with precipitation, we here regress the index onto the precipitation and temperature over East Asia.
We may infer that in 2017 summer, it will be less precipitation in most parts of China, and the temperature will be higher in the north and lower in the south, but there's not enough evidence in my current work.

17. Thanks！